It’s an economic disincentive for Fiat to continue producing them. Sure Fiat could continue to sell those cars, but being on the hook for shoveling Tesla $2bn every few years isn’t a winning long term strategy. Hurts Fiat, helps a company that’s got much better CO2 performance. CO2 will be reduced because it will now be in Fiats financial interest to produce EVs. It certainly won’t happen overnight but the incentives are clear for Fiat.